I've ran into it comment flame wars on /r/history before in my own posts about Alexander the Great.
Greece is Greece, that part is easily understood in itself.
Apparently something went down in 1913 and some split happened that left would be Macedonians a little irked.
What I don't get is Macedonia was considered separate pre Alexander the Great and something the Greeks didn't like being under when Alexander took the reigns of Greece.
After Alexander's Death, there was a push against Macedonia. Eventually, Macedonia was segmented away and dissolved/split up by Rome after the Macedonian Wars (poor Perseus should have killed himself).
What makes it more interesting, is Alexander I of Macedon (not the Great) had to prove his Greek heritage to participate in one of the early Olympics. I don't know how much this is factor in the discussion. Seems like appealing to Homer's Illiad(?) isn't the most thorough treatment of lineage (reminds me of Rome's The Aeneid).
So what I'm seeing here, is some sort of pro Greek state that has been historically recognized as at least a close cousin to Greece since ancient times, but while under Alexander the Great, there was some sort of tension during his reign and today there is some issues with identifying Macedonia as it's own state today vs just as a part of Greece.
Honestly, I don't see the drama since it appears historically, there was just as much animosity as recognizing Macedon as a part of Greece.
By the far, the most impressive thing about Macedon was there good taste in court physicians. ;)
First things first: there are two entities named "Macedonia". One is an independent state in the Balkans (sometimes referred to as the Former Yugoslav Republic of Macedonia, or FYROM) and a region of Greece to the west of West Thrace.
The ancient Kingdom of Macedon was Greek; Alexander and the Macedonians spoke a Hellenic language and considered themselves culturally Greek.
The people in the Republic of Macedonia, on the other hand, speak a Slavic language; Slavs didn't start migrating to the Balkans until the 5th-6th centuries. The language spoken in FYROM is mutually intelligible with Bulgarian, though it has some similarities with Serbian (especially in writing). In the First Balkan War, Macedonia was annexed by Serbia from the Ottoman Empire; however, the majority of the population there had a Bulgarian identity, which led Bulgaria to claim it, starting the Second Balkan War.
After the Second Balkan War and the Treaty of Bucharest, Macedonia remained part of Serbia and became part of the Kingdom of Yugoslavia. After WWII, with the reconstitution of Yugoslavia as a socialist state by Tito, Macedonia became a Socialist Republic within Yugoslavia.
Yugoslavia was non-aligned, unlike Bulgaria which was part of the Warsaw Pact after 1955, so Macedonian identity was promoted over Bulgarian identity. After Yugoslavia was dissolved, this identity remained.
Greek Macedonians object to this since they believe that Macedonian Slavs are claiming their identity as their own, despite having no real historical claim; their culture and heritage are Slavic, and they have no real connection to Alexander the Great. Greece forced FYROM to change their flag from the Vergina Sun, and refuses to use the name "Macedonia", settling on using FYROM for referring to the Macedonian State.
